Building a Shipping Container Cabin

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Solar Panels

Up until two weeks ago I thought I had my solar panel mount plans finalized – a single pole mount to the east of the cabin. That WAS the plan until I found out someone had gone through a lot of effort to steal from my property – more about that later. I’ve now settled on two separate locations and mounting systems for my solar panels. Phase one, last weekend, was installing a permanent roof mount for two panels where theft should not be a concern. Phase two will be a ground mount with a quick attach/detach feature so the panel(s) can be stored in the cabin when I’m away.

The roof mount I constructed this weekend was a simple Unistrut-based mount, of which there are many examples of on the Net. The only thing unique about it is that I used VersaBrackets from S-5 to attach the Unistrut to the roof. There are many different mounting brackets for roofs out there, but the VersaBracket was the only one I could find that would fit between the 1″ corrugations on my metal roof. The rest of the mount consisted of some Unistrut spring nuts and square washers, in addition to various stainless steel bolts, nuts, and washers.

The roof array consists of two Uni-Solar US-64 panels feeding into a Morningstar SunSaver 10 amp charge controller. The Uni-Solar panels are unique because they’re glass-free and virtually unbreakable. They’re also designed so that even if a single cell is damaged, let’s say from an errant bullet, the rest of the cells in the panel will continue to function and provide power. While these two panels alone are not a lot of power, they will easily keep my batteries charged while I’m not there. While I don’t have the solar panel for the ground array yet, it will probably consist of just a single ~200 watt grid tie type panel feeding into a 15 amp MPPT controller.

All is not perfect with this new arrangement though. First off, my 4/12 roof pitch is nowhere near the best angle for solar panels, especially in the winter. The optimum fixed angle for year round use would be somewhere between 45 and 60 degrees. According to PVWATTS, I will lose about 23% of the power in December compared to a 45° angle, although I will gain about 10% in July. Second, and probably more important, is the issue of snow accumulation on the panels. Low angle solar panels obviously do not shed snow as readily compared to higher angles. This means I might need to use a roof rake in the winter if I expect to use these panels at all. In the end it’s probably not that big a deal. I don’t spend a lot of time at the cabin in the dead of winter, and I will eventually have a ground mount array at a more optimum angle to deploy when I’m actually there.

Now about the theft from my property. Several posts back I talked about the rock pile near the cabin that I had removed. In the process of removal, a half dozen or so large (by Wisconsin standards at least) boulders were found – you can see some of them in the pic to the left. I was planning to use them for some landscaping at my entrance. Can you believe someone actually stole these? One of them was large enough that I can only imagine it being moved with heavy machinery. It takes a lot of nerve to come on someone’s property with that type of equipment just to steal some rocks.

On a more pleasant note, at least I didn’t miss the peak colors this fall.

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22 thoughts on “Solar Panels”

Great cabin design. If someone was willing to bring in equipment to steal a large rock, it would seem like there’s a good chance of losing the roof panel as well. All they’d need is a ladder and a cordless grinder or sawzall with a couple of metal cutting blades. You may wish to consider setting up a battery-powered camera recording system, or some other useful security precautions.

There is no shortage of thieves in rural areas. And it can be a lot harder to discourage them or catch them than in town. Fewer likely witnesses, and a smaller population in the area means there’s a not insignificant chance that the thieves will end up being friends or family of local law enforcement.

There are game-trail cameras designed specifically to be hidden and take pictures of anything moving in the target area. Most sporting goods stores should carry them, though they may be hard to find outside of hunting season.

Set one up to cover, at the least, the front of the cabin. Another to watch the road in is not a bad idea. Make sure it can record license plates.

Side opening containers are considerably more expensive, and much less common than standard containers. It also only cost me a few hundred dollars to have all four walls removed by a local welder. Using standard containers will probably save you money in the long run. A side opening container might be worth it though if you wanted to have a solid wall of glass behind the container side door. There are many designs on the net showing this.

The walls were cut out in four foot sections, so it was pretty easy for two people to carry them around.

The panels are currently piled up in the space under the cabin, and I haven’t quite decided what to do with them yet. I thought they might make for a nice corrugated steel Stonehenge type sculpture, but my neighbors don’t need any more reason to question my sanity.

I noticed in one of your other posts, you mentioned 40 ft containers were more cost effective. What are your thoughts on taking a 40, cutting it in half, placing the halves side by side as you did in your layout.

I’d have to seal up 2 ends, but I could utilize the previously removed sides. How expensive was the welding?

You certainly have an interesting idea, but I would be hesitant to cut a perfectly good container in half just to save a few bucks. You will also run into some structural problems if you do it, such as:

1. Loss of the corner blocks on one end to tie into a foundation or even just to set level on a surface.
2. Loss of the structural corner posts on the cut side.
3. Difficulty in mating the removed corrugated panels to the straight middle cut. This would be a welding nightmare.
4. Containers losing square when cut before being attached to a foundation.

My advice would be to not do it. If you need to save money and use a 40 footer, get a double door unit so you can have sliders on both ends. There are a lot of good designs on the net that use 40 foot containers without cutting them in half. I would go with one of those.

I have to agree with Steve. The majority of the structural strength of a container is in it’s frame, I think Steve might have gone over that somewhere in here, and if you were to cut it in half you would lose most of that stability. I don’t think I have to go into too much detail here as most of this Steve has discussed in his blog or comments at one point or another, but always consult a professional or someone who has experience in engineering or architecture when it comes to making choices like this.

Hi Steve, this question is about the flooring in the containers when you bought them…I was reading that some of them are treated with pesticides ( wood floors ) and other chemicals that are bad news. Did you have to remove the flooring and if so how? Excellent design . would be ideal in Northern Ontario where I am from. Take care.

Glad you like it. Yours is a common complaint in winter. I just don’t get up to my cabin as much in winter, and when I do I’m usually not in the mood to tackle any major projects. I do have a few design ideas and miscellaneous topics I hope to cover in the next couple of months, but that’s about it. I also try to keep this blog as focused on technical topics as much as possible, so you may need to be patient just a little longer.

Thank you Steve. Tin Can Cabin is the best site I have found in all my container home building research. Your photography and writing skills come together to create a blog that is easy to read and nice looking. Thanks again for sharing and I look forward to your future posts.

What about etching the glass of your solar panels with unique ID information to help deter theft? The same thing that is being done with auto glass? Least it would readily identify the panels so that the police will have something. Given that solar is still not that common, it would be easy to find new installations are being done.

Great job! Just wanna comment that you should relocate your solar panels to another spot where it is clear from any shadows. The shadow will cause the panels to be in efficient and possibly harm your system in the long run.

There is no shading for three seasons of the year, and the small amount of shading that occurs during summer mornings and evenings is insignificant in my opinion. What is more important to me, if you read the post, is a secure location away from thieves. I’m also not sure how any inefficiency might harm my system. The AGM batteries that I use in my system have such a low self discharge they can easily go months without a charge.

I’ve enjoyed looking through your posts because of your emphasis the need for and difficulty of maintaining security in a rural area. (In my chosen spot, people might steal the whole building for scrap, piece by piece!) Have you had any bullets aimed at the walls (from the outside), and did the bullets penetrate?
Thanks,
DH

No bullet holes in the cabin so far, but the sign at the end of my driveway has plenty. I have already thought about how I would fix one though. Inject some Great Stuff foam sealant into the hole (I always keep some at the cabin), apply some Bondo, sand it down, and then paint to match. Duct tape would be a good temporary patch until I could get some Bondo. And while the outside might be an easy fix, I don’t even want to contemplate the damage it could do to the inside.

As far as bullet resistance, not so much. Container walls are only 14 gauge steel. It might stop bird shot, 22LR, and some lower velocity handgun rounds, but that’s about it.

Hi Steve, hello from Australia 🙂
In regards to your solar system, could you provide details of how your standalone solar system works, are you using a power inverter if so what wattage (eg 200w etc) and how are your storage batteries connected (I have a 120ah 12volt deep cycle battery that I use in my caravan (aka motor home). I was considering buying two 120w solar panels with a 200w or so grid tie inverter that will supplement my existing mains power to the house from the grid. Just after some ideas 🙂